The following is digested from the book
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is a product derived from the husks of the coconut.
Visually it looks like peat.
It's air capacity is about 30%.
Coir is most suited as a run to waste medium.
Coir can become saturated and it is not truly inert medium.
This means that the nutrient will change over a short period (due to the nutrient collecting micro and macro elements as it passes through the coir.
Coir tends to release potassium and to withold calcium.
For this reason it is desirable to use a nutrient that is blended specifically for coir.
Coir has a remarkable capacity to protect the plants root system in times of heat
It also tends to promote vigorous and healthy root development.
Plant growth tends to be very consistant with coir.
Coir is very tolerant of over and under watering, which makes it a very forgiving growing medium.
Coir has a very strong cation exchange ability, which means it can hold and release nutrient elements based on the plants needs.
Coir tends to retain nutrient salts. because of this, less nutrient (lower ec) is required.
On a less positive note, coir can also contain high levels of sodium (salt).
If your growing in coir be aware that this can be a potential problem.
Either purchase a pre-flushed coir product or flush ph (5.5-6.0) stabilised water through the coir prior to use.
Measure the ec of the water and then measure the ec of the run off.
When they are the same, it is ready for use.
Large amounts of potassium are naturally present in coir.
Potassium competes with calcium and magnesium... buffering and plant nutrition needs to compensate for this!!
For this reason there are several nutrients that are specifically formulated with the coco coir's unique characteristics in mind.
By using a nutrient specifically formulated for the coir based system, you are ensuring that your plants are receiving the best possible nutritient package.
[As coco gets old it breaks down and releases P and K.
That's why the coco nutrients are lower in P and K, to allow for the additional nutrients released by the medium.
In the early stages the coco is inert and therefore a "standard" grow formula works well.
As you enter flower that is why It is usually strongly suggested that one purchase and use a Coco specific nutrient formula. (for best possible results.)
A run to waste "runoff" of 10-20% of the volume watered each watering is the most common and usual type recommendation to avoid the possibility with salt(s) build-up in the coco media.